Control scene contamination. The lead investigator must make sure that scene and the evidence collected are not contaminated, and must make sure personnel
are safe.

The investigator should ensure that evidence processing personnel:

Use clean protective outergarments and equipment for each scene.

Obtain control samples as needed (e.g., evidence containers, swabs of equipment and personnel).

Package collected evidence in a manner that prevents loss, degradation or contamination.

Package, store and transport evidence from different scenes or searches in separate external containers.

Identify, collect, preserve, inventory, package and transport evidence. The investigation team should search for physical evidence that establishes that a crime was committed, and link elements
of the crime to possible suspects.

To maximize the recovery and evaluation of all types of physical evidence, the investigator should: